U.S. patent number 6,911,297 [Application Number 10/465,000] was granted by the patent office on 2005-06-28 for photoresist compositions.
This patent grant is currently assigned to Arch Specialty Chemicals, Inc.. Invention is credited to Andrew Blakeney, David Brzozowy, Lawerence Ferreira, John P. Hatfield, J. Thomas Kocab.
United States Patent |
6,911,297 |
Brzozowy , et al. |
June 28, 2005 |
Photoresist compositions
Abstract
Radiation sensitive compositions for use in producing a
patterned image on a substrate comprise: a) a first photoacid
generator compound which comprises one or more compounds of the
structure (A); ##STR1## b) a second photoacid generator compound
which comprises one or more compounds of the structure (B);
##STR2## c) a polymer component comprising an alkali soluble resin
component whose alkali solubility is suppressed by the presence of
acid sensitive moieties and whose alkali solubility is returned by
treatment with an acid and, optionally, heat; wherein said polymer
comprises one or more polymers comprising the monomer unit (C);
##STR3## and d) a solvent.
Inventors: |
Brzozowy; David (Bristol,
RI), Kocab; J. Thomas (Wyoming, RI), Hatfield; John
P. (Hope Valley, RI), Ferreira; Lawerence (Fall River,
MA), Blakeney; Andrew (Seekonk, MA) |
Assignee: |
Arch Specialty Chemicals, Inc.
(Norwalk, CT)
|
Family
ID: |
30000762 |
Appl.
No.: |
10/465,000 |
Filed: |
June 19, 2003 |
Current U.S.
Class: |
430/270.1;
430/281.1; 430/286.1; 430/322; 430/328; 430/330 |
Current CPC
Class: |
G03F
7/0045 (20130101); G03F 7/0046 (20130101); G03F
7/0392 (20130101); G03F 7/40 (20130101); G03F
7/0397 (20130101) |
Current International
Class: |
G03F
7/038 (20060101); G03F 7/004 (20060101); G03F
007/004 () |
Field of
Search: |
;430/270.1,281.1,286.1,322,328,330 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2002131898 |
|
May 2002 |
|
JP |
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2002131898 |
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May 2002 |
|
JP |
|
Other References
English language abstract of JP 2002-131898. .
PCT International Search Report based off of PCT/US03/21031 with a
filing date Aug. 25, 2004..
|
Primary Examiner: Walke; Amanda
Attorney, Agent or Firm: Ohlandt, Greeley Ruggiero &
Perle LLP
Parent Case Text
RELATED APPLICATION
This application claims priority from U.S. Provisional Application
No. 60/391,850, filed Jun. 26, 2002.
Claims
We claim:
1. A radiation sensitive composition comprising: a) a first
photoacid generator (PAG) compound P1, which comprises one or more
compounds of the structure (A); b) a second photoacid generator
compound P2 which comprises one or more compounds of the structure
(B); c) a polymer component comprising an alkali soluble resin
component whose alkali solubility is suppressed by the presence of
acid sensitive moieties and whose alkali solubility is returned by
treatment with an acid and, optionally, heat; wherein said polymer
comprises one or more polymers comprising the monomer unit (C); and
d) a solvent; wherein structure (A) has the formula: ##STR23##
wherein R.sup.1 and R.sup.2 are each independently selected from
the group consisting of C.sub.1 -C.sub.12 fluoroalkyl groups or
together R.sup.1 and R.sup.2 are joined with the N to form a
(F.sub.2 C).sub.y N ring where y=4-12; R.sup.3, R.sup.4, and
R.sup.5 are each independently selected from the group consisting
of unsubstituted aryl, alkyl or alpha-ketomethyl groups or such
groups substituted with an acid sensitive group, or R.sup.3 and
R.sup.4 together with the S atom form a cycloalkylsulfonium ring;
R.sup.6 to R.sup.11 and R.sup.6' to R.sup.11' are independently
selected from the group consisting of branched or linear alkyl,
alkoxy, halogen, hydrogen, OCO.sub.2 G, OCH.sub.2 CO.sub.2 G, and
OG where G=an acid sensitive group; wherein structure (B) has the
formula: ##STR24## wherein each R.sup.12 is independently selected
from the group consisting of a linear, cyclic, or branched C.sub.1
-C.sub.8 fluoroalkyl group, substituted or unsubstituted phenyl
group, substituted or unsubstituted naphthalene group, C.sub.6
-C.sub.12 cyclic or alicyclic hydrocarbon, and a linear, cyclic, or
branched C.sub.1 -C.sub.8 alkyl group; and wherein monomeric unit
(C) has the formula: ##STR25## wherein R.sup.13 is selected from
the group consisting of H, C.sub.1 -C.sub.4 lower alkyl, CN, and
CH.sub.2 CO.sub.2 R.sup.20 ; R.sup.14 and R.sup.15 are each
independently selected from the group consisting of H, linear or
branched C.sub.1 -C.sub.4 alkyl, and halogen; R.sup.16 is selected
from the group consisting of H and branched or linear C.sub.1
-C.sub.4 alkyl; R.sup.17 is selected from the group consisting of
substituted or unsubstituted phenyl, a substituted or unsubstituted
linear, branched or cyclic C.sub.1 -C.sub.20 alkyl, optionally
containing an ether or ester group, a substituted or unsubstituted
phenylalkylene, and a substituted or unsubstituted C.sub.6
-C.sub.20 cyclic alkylene ; R.sup.18 and R.sup.19 are each
independently selected from the group consisting of H, linear or
branched or cyclic C.sub.1 -C.sub.14 alkyl, and C.sub.7 -C.sub.14
alicyclic; R.sup.20 is selected from the group consisting of a
C.sub.1 -C.sub.14 branched, linear or cyclic alkyl, substituted or
unsubstituted phenyl, and C.sub.7 -C.sub.14 alicyclic group.
2. The radiation sensitive composition of claim 1 wherein the total
amount of photoactive generator content in the composition is from
about 0.05 to about 20 wt % of the solids content of the
composition and photoactive generator compound P1 comprises from
about 25 to about 99 wt % and the second photoactive generator
compound P2 comprises from about 1 to about 75 wt % of the total
photoactive generator content of the composition.
3. The radiation sensitive composition of claim 1 wherein the total
amount of photoactive generator content in the composition is from
about 1 to about 15 wt % of the solids content of the composition
and photoactive generator compound P1 comprises from about 35 to
about 90 wt % and the second photoactive generator compound P2
comprises from about 10 to about 65 wt % of the total photoactive
generator content of the composition.
4. The radiation sensitive composition of claim 1 wherein the total
amount of photoactive generator content in the composition is from
about 0.05 to about 20 wt % of the solids content of the
composition and photoactive generator compound P1 comprises from
about 60 to about 80 wt % and the second photoactive generator
compound P2 comprises from about 20 to about 40 wt % of the total
photoactive generator content of the composition.
5. The radiation sensitive composition of claim 1 wherein the
polymer component comprises from about 75 to about 95 wt % of the
total solids content of the composition.
6. The radiation sensitive composition of claim 1 wherein in
structure (A) M is S and R.sup.1 and R.sup.2 are C.sub.1 -C.sub.6
perfluoroalkyl and in structure (B) R.sup.12 is linear, branched or
cyclic C.sub.1 -C.sub.7 alkyl.
7. The radiation sensitive composition of claim 6 wherein R.sup.1
and R.sup.2 are different C.sub.1 -C.sub.6 perfluoroalkyl
groups.
8. The radiation sensitive composition of claim 1 wherein in
photoactive generator compound P1 the (R.sup.1 SO.sub.2 NSO.sub.2
R.sup.2).sup.- group is selected from the group consisting of
(CF.sub.3 SO.sub.2 NSO.sub.2 CF.sub.3).sup.- (CF.sub.3 CF.sub.2
CF.sub.2 CF.sub.2 CF.sub.2 CF.sub.2 CF.sub.2 CF.sub.2 SO.sub.2
NSO.sub.2 CF.sub.3).sup.- (CF.sub.3 CF.sub.2 SO.sub.2 NSO.sub.2
NCF.sub.2 CF.sub.3).sup.- ##STR26## (CF.sub.3 CF.sub.2 CF.sub.2
CF.sub.2 SO.sub.2 NSO.sub.2 CF.sub.2 CF.sub.2 CF.sub.2
CF.sub.3).sup.- (CF.sub.3 CF.sub.2 SO.sub.2 NSO.sub.2
CF.sub.3).sup.- (CF.sub.3 CF.sub.2 CF.sub.2 SO.sub.2 NSO.sub.2
CF.sub.2 CF.sub.2 CF.sub.2 CF.sub.2 CF.sub.3).sup.- ##STR27##
(CF.sub.3 CF.sub.2 CF.sub.2 CF.sub.2 SO.sub.2 NSO.sub.2
CF.sub.3).sup.- (CF.sub.3 CF.sub.2 CF.sub.2 CF.sub.2 CF.sub.2
CF.sub.2 CF.sub.2 CF.sub.2 SO.sub.2 NSO.sub.2 CF.sub.2 CF.sub.2
CF.sub.2 CF.sub.2 CF.sub.2 CF.sub.2 CF.sub.2 CF.sub.3).sup.-
(CF.sub.3 (CF.sub.2).sub.7 SO.sub.2 NSO.sub.2 CF.sub.3).sup.-
and the substituted or unsubstituted R.sup.3 R.sup.4 R.sup.5 S+
group is selected from the group consisting of: ##STR28## ##STR29##
##STR30## ##STR31## the diaryl iodonium cation is are selected from
the group consisting of: ##STR32## and in the second photoacid
generator compound P2 each R.sup.12 is independently selected from
the group consisting of methyl, ethyl, n-butyl, t-butyl,
cyclohexyl, perfluorobutyl, phenyl, methoxyphenyl, bromophenyl,
4-methoxynaphthalene, naphthalene and adamantly; and in the polymer
comprising monomeric unit (C), R.sup.13, R.sup.14, R.sup.15,
R.sup.16, R.sup.18, and R.sup.19 =H and R.sup.17 is selected from
the group consisting of C.sub.1 -C.sub.4 linear or branched alkyl
and a substituted or unsubstituted C.sub.6 -C.sub.20 cyclic
alkylene.
9. The radiation sensitive composition of claim 8 wherein the
polymer component comprises an additional monomer unit selected
from the group consisting of acrylates, methacrylates, vinyl
ethers, vinyl esters, substituted and unsubstituted styrenes.
10. The radiation sensitive composition of claim 1 wherein the
polymer component comprises an additional monomeric unit that is
hydroxystyrene.
11. The radiation sensitive composition of claim 1 wherein
photoactive generator compound P1 is selected from the group
consisting of 4-(1-butoxyphenyl)diphenylsulfonium
bis-(perfluorobutanesulfonyl)imide,
4-(1-butoxyphenyl)diphenylsulfonium
bis-(perfluoroethanesulfonyl)imide,
2,4,6-trimethylphenyldiphenylsulfonium
bis-perfluorobutanesulfonyl)imide,
2,4,6-trimethylphenyldiphenylsulfonium
bis-(perfluoroethanesulfonyl)imide, toluenediphenylsulfonium
bis-(perfluorobutanesulfonyl)imide, toluenediphenylsulfonium
bis-(perfluoroethanesulfonyl)imide,
toluenediphenylsulfonium-(trifluoromethyl
perfluorobutylsulfonyl)imide,
tris-(tert-butylphenyl)sulfonium-(trifluoromethyl
perfluorobutylsulfonyl)imide, tris-(tert-butylphenyl)sulfonium
bis-(perfluorobutanesulfonyl)imide,
tris-(tert-butylphenyl)sulfonium-bis-(trifluoromethanesulfonyl)imide
the photoactive generator compound P2 is
bis(tert-butylsulfonyl)imide, and the polymer component is selected
from
4-[1-(2-cyclohexylethoxy)-ethoxy]styrene-co-4-[1-(t-butoxy)-ethoxy]styrene
-co-4-hydroxy styrene-co-4-t-butylstyrene copolymer,
[4-(1-ethoxyethoxy)styrene-co-4-hydroxystyrene, and mixtures
thereof.
12. A process for producing a patterned image on a substrate, the
process comprising the steps of: a. coating on a suitable substrate
a radiation sensitive composition of claim 1, thereby forming a
coated substrate; b. prebaking the coated substrate; c. exposing
the prebaked coated substrate to actinic radiation; d. optionally
post-baking the exposed coated substrate; e. developing the exposed
coated substrate with a developer thereby forming an uncured relief
image on the coated substrate; and f. baking the developed coated
substrate at an elevated temperature thereby curing the image.
13. A process for producing a patterned image on a substrate, the
process comprising the steps of: a. coating on a suitable substrate
a radiation sensitive composition of claim 2, thereby forming a
coated substrate; b. prebaking the coated substrate; c. exposing
the prebaked coated substrate to actinic radiation; d. optionally
post-baking the exposed coated substrate; e. developing the exposed
coated substrate with a developer thereby forming an uncured relief
image on the coated substrate; and f. baking the developed coated
substrate at an elevated temperature thereby curing the image.
14. A process for producing a patterned image on a substrate, the
process comprising the steps of: a. coating on a suitable substrate
a radiation sensitive composition of claim 3, thereby forming a
coated substrate; b. prebaking the coated substrate; c. exposing
the prebaked coated substrate to actinic radiation; d. optionally
post-baking the exposed coated substrate; e. developing the exposed
coated substrate with a developer thereby forming an uncured relief
image on the coated substrate; and f. baking the developed coated
substrate at an elevated temperature thereby curing the image.
15. A process for producing a patterned image on a substrate, the
process comprising the steps of: a. coating on a suitable substrate
a radiation sensitive composition of claim 4, thereby forming a
coated substrate; b. prebaking the coated substrate; c. exposing
the prebaked coated substrate to actinic radiation; d. optionally
post-baking the exposed coated substrate; e. developing the exposed
coated substrate with a developer thereby forming an uncured relief
image on the coated substrate; and f. baking the developed coated
substrate at an elevated temperature thereby curing the image.
16. A process for producing a patterned image on a substrate, the
process comprising the steps of: a. coating on a suitable substrate
a radiation sensitive composition of claim 5, thereby forming a
coated substrate; b. prebaking the coated substrate; c. exposing
the prebaked coated substrate to actinic radiation; d. optionally
post-baking the exposed coated substrate; e. developing the exposed
coated substrate with a developer thereby forming an uncured relief
image on the coated substrate; and f. baking the developed coated
substrate at an elevated temperature thereby curing the image.
17. A process for producing a patterned image on a substrate, the
process comprising the steps of: a. coating on a suitable substrate
a radiation sensitive composition of claim 6, thereby forming a
coated substrate; b. prebaking the coated substrate; c. exposing
the prebaked coated substrate to actinic radiation; d. optionally
post-baking the exposed coated substrate; e. developing the exposed
coated substrate with a developer thereby forming an uncured relief
image on the coated substrate; and f. baking the developed coated
substrate at an elevated temperature thereby curing the image.
18. A process for producing a patterned image on a substrate, the
process comprising the steps of: a. coating on a suitable substrate
a radiation sensitive composition of claim 7, thereby forming a
coated substrate; b. prebaking the coated substrate; c. exposing
the prebaked coated substrate to actinic radiation; d. optionally
post-baking the exposed coated substrate; e. developing the exposed
coated substrate with a developer thereby forming an uncured relief
image on the coated substrate; and f. baking the developed coated
substrate at an elevated temperature thereby curing the image.
19. A process for producing a patterned image on a substrate, the
process comprising the steps of: a. coating on a suitable substrate
a radiation sensitive composition of claim 8, thereby forming a
coated substrate; b. prebaking the coated substrate; c. exposing
the prebaked coated substrate to actinic radiation; d. optionally
post-baking the exposed coated substrate; e. developing the exposed
coated substrate with a developer thereby forming an uncured relief
image on the coated substrate; and f. baking the developed coated
substrate at an elevated temperature thereby curing the image.
20. A process for producing a patterned image on a substrate, the
process comprising the steps of: a. coating on a suitable substrate
a radiation sensitive composition of claim 9, thereby forming a
coated substrate; b. prebaking the coated substrate; c. exposing
the prebaked coated substrate to actinic radiation; d. optionally
post-baking the exposed coated substrate; e. developing the exposed
coated substrate with a developer thereby forming an uncured relief
image on the coated substrate; and f. baking the developed coated
substrate at an elevated temperature thereby curing the image.
21. A process for producing a patterned image on a substrate, the
process comprising the steps of: a. coating on a suitable substrate
a radiation sensitive composition of claim 10, thereby forming a
coated substrate; b. prebaking the coated substrate; c. exposing
the prebaked coated substrate to actinic radiation; d. optionally
post-baking the exposed coated substrate; e. developing the exposed
coated substrate with a developer thereby forming an uncured relief
image on the coated substrate; and f. baking the developed coated
substrate at an elevated temperature thereby curing the image.
22. A process for producing a patterned image on a substrate, the
process comprising the steps of: a. coating on a suitable substrate
a radiation sensitive composition of claim 11, thereby forming a
coated substrate; b. prebaking the coated substrate; c. exposing
the prebaked coated substrate to actinic radiation; d. optionally
post-baking the exposed coated substrate; e. developing the exposed
coated substrate with a developer thereby forming an uncured relief
image on the coated substrate; and f. baking the developed coated
substrate at an elevated temperature thereby curing the image.
Description
FIELD OF THE INVENTION
This invention relates to photosensitive compositions with high
resolution, excellent photospeed and excellent depth of focus while
at the same time providing for decreasing line width and film
thickness useful in the manufacture of semiconductor devices, and
to the process of using such photosensitive compositions for
producing imaged patterns on substrates for the production of such
semiconductor devices.
BACKGROUND TO THE INVENTION
Advanced resists usually employ a technique called chemical
amplification in which an acid generated by photolysis catalyzes a
solubility switch from alkali insoluble to alkali soluble by
removal of an acid sensitive group protecting an alkali
solubilizing moiety. Polymers frequently used in this type of
photosensitive composition include acetals derived from reaction of
vinyl ethers with a polymer containing hydroxystyrene units.
Chemically amplified resists based on acetal protected
polyhydroxystyrene, such as found in U.S. Pat. Nos. 5,928,818,
5,834,531, and 5,558,976, which are incorporated herein by
reference, are well known. Preferred characteristics and often
advantages over other chemically amplified systems include lower
temperature in processing conditions, and lower sensitivity to bake
temperature variations.
As the semiconductor industry requires smaller and smaller
features, the photoresists employed in the manufacture of
semiconductor devices require improved resolution. As the required
resolution becomes smaller, previously minor problems become more
important to solve. Two such problems are a dependence of
performance on film thickness and line collapse. As resolution
requires increase, it is also more important to obtain as high a
depth of focus as possible to help maintain processing latitude.
The objective of this invention is to provide a photosensitive
composition with high resolution, excellent photospeed, and
excellent DOF at the same time as decreasing line collapse and film
thickness dependence.
SUMMARY OF THE INVENTION
This invention concerns radiation sensitive compositions useful in
the manufacture of semiconductor devices. These radiation sensitive
compositions comprise: a) a first photoacid generator (PAG)
compound P1, which comprises one or more compounds of the structure
(A); b) a second photoacid generator compound P2 which comprises
one or more compounds of the structure (B); c) a polymer component
comprising an alkali soluble resin component whose alkali
solubility is suppressed by the presence of acid sensitive moieties
and whose alkali solubility is returned by treatment with an acid
and, optionally, heat; wherein said polymer comprises one or more
polymers comprising the monomer unit (C); and d) a solvent,
wherein structure (A) is the formula: ##STR4##
where R.sup.1 and R.sup.2 are each independently C.sub.1 -C.sub.12
fluoroalkyl groups or together R.sup.1 and R.sup.2 are joined with
the N to form a (F.sub.2 C).sub.y N ring where y=4-12; R.sup.3,
R.sup.4, and R.sup.5 are each independently selected from
unsubstituted aryl, alkyl or alpha-ketomethyl groups and such
groups substituted with an acid sensitive group, or R.sup.3 and
R.sup.4 together with the S atom form a cycloalkylsulfonium ring;
R.sup.6 to R.sup.11 and R.sup.6' to-R.sup.11' are each
independently selected from branched or linear alkyl, alkoxy,
halogen, hydrogen, OCO.sub.2 G, OCH.sub.2 CO.sub.2 G, or OG where
G=an acid sensitive group; wherein structure (B) has the formula:
##STR5##
where each R.sup.12 is independently selected from a linear,
cyclic, or branched C.sub.1 -C.sub.8 fluoroalkyl group, substituted
or unsubstituted phenyl group, substituted or unsubstituted
naphthalene group, C.sub.6 -C.sub.12 cyclic or alicyclic
hydrocarbon, or a linear, cyclic, or branched C.sub.1 -C.sub.8
alkyl group; and wherein monomeric unit (C) has the formula:
##STR6##
wherein R.sup.13 is selected from H, C.sub.1 -C.sub.4 lower alkyl,
CN, or CH.sub.2 CO.sub.2 R.sup.20 ; R.sup.14 and R.sup.15 are each
independently selected from H, linear or branched C.sub.1 -C.sub.4
alkyl, or halogen; R.sup.16 is H, or branched or linear C.sub.1
-C.sub.4 alkyl; R.sup.17 is selected from substituted or
unsubstituted phenyl, a substituted or unsubstituted linear,
branched or cyclic C.sub.1 -C.sub.20 alkyl, optionally containing
an ether or ester group, a substituted or unsubstituted
phenylalkylene or a substituted or unsubstituted C.sub.6 -C.sub.20
cyclic alkylene; R.sup.18 and R.sup.19 are independently selected
from H, linear or branched or cyclic C.sub.1 -C.sub.14 alkyl, or
C.sub.7 -C.sub.14 alicyclic; R.sup.20 is selected from a C.sub.1
-C.sub.14 branched linear or cyclic alkyl, substituted or
unsubstituted phenyl, or C.sub.7 -C.sub.14 alicyclic group.
The photosensitive compositions of this invention may further
comprise additives such as nitrogenous bases, dissolution
inhibitors, coating additives, dyes, surfactants, and the like.
Preferred first photoacid generator compounds P1 are those
compounds of structure A in which M=S and R.sup.1 and R.sup.2 are
C.sub.1 -C.sub.6 perfluoroalkyl. Most preferred compounds P1 are
those compounds of structure (A) in which M=S, R.sup.1 and R.sup.2
are C.sub.1 -C.sub.6 perfluoroalkyl, and R.sup.1 is different from
R.sup.2.
Preferred second photoacid generator compounds P2 are those
compounds of structure (B) in which R.sup.12 is linear, branched,
or cyclic C.sub.1 -C.sub.7 alkyl.
Preferred polymers comprising the monomer unit (C) are those in
which R.sup.13, R.sup.14, R.sup.15, R.sup.16, R.sup.18, and
R.sup.19 =H. More preferred polymers comprising the monomer unit C
are those in which R.sup.13, R.sup.14, R.sup.15, R.sup.16,
R.sup.18, and R.sup.19 =H and R.sup.17 is selected from C.sub.1
-C.sub.4 linear or branched alkyl, or a substituted or
unsubstituted C.sub.6 -C.sub.20 cyclic alkylene or a substituted or
unsubstituted linear, branched or cyclic C.sub.1 -C.sub.20 alkyl,
optionally containing an ether or ester group. Most preferred
polymers comprising the monomer unit (C) are those in which
R.sup.13, R.sup.14, R.sup.15, R.sup.16, R.sup.18, and R.sup.19,=H
and R.sup.17 is C.sub.1 -C.sub.4 linear or branched alkyl, or a
substituted or unsubstituted C.sub.6 -C.sub.20 cyclic alkylene.
DETAILED DESCRIPTION OF INVENTION AND PREFERRED EMBODIMENTS
The radiation sensitive compositions of this invention
comprise:
a) a first photoacid generator (PAG) compound P1, which comprises
one or more compounds of the structure (A);
b) a second photoacid generator compound P2 which comprises one or
more compounds of the structure (B);
c) a polymer component comprising an alkali soluble resin component
whose alkali solubility is suppressed by the presence of acid
sensitive moieties and whose alkali solubility is returned by
treatment with an acid and, optionally, heat; wherein said polymer
comprises one or more polymers comprising the monomer unit (C);
and
d) a solvent;
wherein the structures (A), (B) and monomeric unit (C) are as
follows: ##STR7##
where R.sup.1 and R.sup.2 are each independently selected from
C.sub.1 -C.sub.12 fluoroalkyl groups or together R.sup.1 and
R.sup.2 are joined with the N to form a (F.sub.2 C).sub.y N ring
where y=4-12; R.sup.3, R.sup.4, and R.sup.5 are each independently
selected from unsubstituted aryl, alkyl or alpha-ketomethyl groups
and such groups substituted with an acid sensitive group or R.sup.3
and R.sup.4 together with the S atom form a cycloalkylsulfonium
ring; R.sup.6 to R.sup.11 and R.sup.6' to R.sup.11' are each
independently selected from branched or linear alkyl, alkoxy,
halogen, hydrogen, OCO.sub.2 G, OCH.sub.2 CO.sub.2 G, or OG where
G=an acid sensitive group; ##STR8##
where each R.sup.12 is independently selected from a linear,
cyclic, or branched C.sub.1 -C.sub.8 fluoroalkyl group, substituted
or unsubstituted phenyl group, substituted or unsubstituted
naphthalene group, C.sub.6 -C.sub.12 cyclic or alicyclic
hydrocarbon, or a linear, cyclic, or branched C.sub.1 -C.sub.8
alkyl group; ##STR9##
wherein R.sup.13 is selected from H, C.sub.1 -C.sub.4 lower alkyl,
CN, or CH.sub.2 CO.sub.2 R.sup.20 ; R.sup.14 and R.sup.15 are each
independently selected from H, linear or branched C.sub.1 -C.sub.4
alkyl, or halogen; R.sup.16 is selected from H, or branched or
linear C.sub.1 -C.sub.4 alkyl; R.sup.17 is selected from
substituted or unsubstituted phenyl, a substituted or unsubstituted
linear, branched or cyclic C.sub.1 -C.sub.20 alkyl, optionally
containing an ether or ester group, a substituted or unsubstituted
phenylalkylene or a substituted or unsubstituted C.sub.6 -C.sub.20
cyclic alkylene; R.sup.18 and R.sup.19 are each independently
selected from H, linear or branched or cyclic C.sub.1 -C.sub.14
alkyl, or C.sub.7 -C.sub.14 alicyclic; R.sup.20 is selected from a
C.sub.1 -C.sub.14 branched linear or cyclic alkyl, substituted or
unsubstituted phenyl, or C.sub.7 -C.sub.14 alicyclic.
The total photoacid generator content of the photosensitive
composition is 0.05 to 20 wt % of the solids content. The preferred
range is from about 1 to about 15 wt %. The first photoacid
generator compound P1 comprises about 25 to about 99 wt % of the
total photoacid generator content. The second photoacid generator
compound P2 comprises about 1 to about 75 wt % of the total amount
of photoacid generator. Additional photoacid generators may be
present. Preferably, the first photoacid generator compound P1
comprises about 35 to about 90 wt % of the total photoacid
generator content. Most preferably, the first photoacid generator
compound P1 comprises about 60 to about 80 wt % of the total
photoacid generator content. Preferably, the second photoacid
generator compound P2 comprises about 10 to about 65 wt % of the
total amount of photoacid generator content. Most preferably, the
second photoacid generator compound P2 comprises about 20 to about
40 wt % of the total amount of photoacid generator content.
The polymer component comprising an alkali soluble resin component
whose alkali solubility is suppressed by the presence of acid
sensitive moieties and whose alkali solubility is returned by
treatment with an acid comprises from about 75 wt % to about 99 wt
% of the solids content of the photosensitive composition. The
preferred concentration is from about 80 wt % to about 95 wt %.
The choice of solvent for the photoresist composition and the
concentration thereof depends principally on the type of
functionalities incorporated in the acid labile polymer, the
photoacid generator, and the coating method. The solvent should be
inert, should dissolve all the components in the photoresist,
should not undergo any chemical reaction with the components and
should be re-removable on drying after coating. Suitable solvents
for the photoresist composition may include ketones, ethers and
esters, such as methyl ethyl ketone, methyl isobutyl ketone,
2-heptanone, cyclopentanone, cyclohexanone, 2-methoxy-1-propylene
acetate, 2-methoxyethanol, 2-ethoxyothanol, 2-ethoxyethyl acetate,
l-methoxy-2-propyl acetate, 1,2-dimethoxy ethane ethyl acetate,
cellosolve acetate, propylene glycol monoethyl ether acetate,
methyl lactate, ethyl lactate, methyl pyruvate, ethyl pyruvate,
methyl 3-methoxypropionate, ethyl 3-methoxypropionate,
N-methyl-2-pyrrolidone, 1,4-dioxane, ethylene glycol monoisopropyl
ether, diethylene glycol monoethyl ether, diethylene glycol
monomethyl ether, diethylene glycol dimethyl ether, and the like.
Preferred solvents are propylene glycol monomethyl ether acetate,
2-heptanone, and ethyl lactate.
The solids content of the resist may range from about 1 wt % to
about 25 wt % depending on the photoresist thickness desired. The
preferred solids content is from about 5 to about 15 wt %.
First photoacid generator compound P1 comprises one or more
compounds of the structure (A). ##STR10##
where R.sup.1 and R.sup.2 are each independently selected from
C.sub.1 -C.sub.12 fluoroalkyl groups or together R.sup.1 and
R.sup.2 are joined with the N to form a (F.sub.2 C).sub.y N ring
where y=4-12; R.sup.3, R.sup.4, and R.sup.5 are each independently
selected from substituted, substituted with an acid sensitive
group, or unsubstituted aryl, alkyl or alpha-ketomethyl groups, or
R.sup.3 and R.sup.4 together form a cycloalkylsulfonium ring;
R.sup.6 to R.sup.11 and R.sup.6' to R.sup.11' are each
independently selected from a branched or linear alkyl, alkoxy,
halogen, hydrogen, OCO.sub.2 G, OCH.sub.2 CO.sub.2 G, or OG where
G=an acid sensitive group.
Examples of P1 may be synthesized by reaction of a salt of
(SO.sub.2 R.sup.1)(SO.sub.2 R.sup.2)N.sup.- with a salt of R.sub.x
M.sup.+ in a solvent. The preferred counter ion for (SO.sub.2
R.sup.1)(SO.sub.2 R.sup.2)N.sup.- is sodium and the preferred
counter ion for R.sub.x M.sup.+ is the mesylate. The preferred
solvent is water.
Suitable (R.sup.1 SO.sub.2 NSO.sub.2 R.sup.2).sup.- groups include
but are not limited to
(CF.sub.3 CF.sub.2 CF.sub.2 CF.sub.2 CF.sub.2 CF.sub.2 CF.sub.2
CF.sub.2 SO.sub.2 NSO.sub.2 CF.sub.3).sup.- (CF.sub.3 SO.sub.2
NSO.sub.2 CF.sub.3).sup.- (CF.sub.3 CF.sub.2 SO.sub.2 NSO.sub.2
NCF.sub.2 CF.sub.3).sup.- ##STR11## (CF.sub.3 CF.sub.2 CF.sub.2
CF.sub.2 SO.sub.2 NSO.sub.2 CF.sub.2 CF.sub.2 CF.sub.2
CF.sub.3).sup.-
(CF.sub.3 CF.sub.2 SO.sub.2 NSO.sub.2 CF.sub.3).sup.- (CF.sub.3
CF.sub.2 CF.sub.2 CF.sub.2 SO.sub.2 NSO.sub.2 CF.sub.3).sup.-
(CF.sub.3 CF.sub.2 CF.sub.2 CF.sub.2 CF.sub.2 CF.sub.2 CF.sub.2
CF.sub.2 SO.sub.2 NSO.sub.2 CF.sub.2 CF.sub.2 CF.sub.2 CF.sub.2
CF.sub.2 CF.sub.2 CF.sub.2 CF.sub.3).sup.- (CF.sub.3 CF.sub.2
CF.sub.2 SO.sub.2 NSO.sub.2 CF.sub.2 CF.sub.2 CF.sub.2 CF.sub.2
CF.sub.3).sup.- (CF.sub.3 (CF.sub.2).sub.7 SO.sub.2 NSO.sub.2
CF.sub.3).sup.- ##STR12##
Suitable substituted or unsubstituted aryl R.sup.3 R.sup.4 R.sup.5
S.sup.+ groups include but are not limited to: ##STR13##
##STR14##
Suitable substituted aryl R.sup.3 R.sup.4 R.sup.5 S.sup.+ groups
with an acid sensitive group include but are not limited to:
##STR15##
Suitable R.sup.3 R.sup.4 R.sup.5 S.sup.+ groups containing alkyl or
cycloalkyl groups include but are not limited to: ##STR16##
Suitable R.sup.3 R.sup.4 R.sup.5 S.sup.+ groups containing
alpha-ketomethyl groups include but are not limited to:
##STR17##
The diaryl iodonium cations include but are not limited to:
##STR18##
Second photoacid generator compound P2 comprises one or more
compounds of the structure (B) ##STR19##
where each R.sup.12 is independently selected from a linear,
cyclic, or branched C.sub.1 -C.sub.8 fluoroalkyl group, substituted
or unsubstituted phenyl group, substituted or unsubstituted
naphthalene group, C.sub.6 -C.sub.12 cyclic or alicyclic
hydrocarbon, or a linear, cyclic, or branched C.sub.1 -C.sub.8
alkyl group. Examples of suitable R.sup.12 groups include but are
not limited to Me, Et, n-Bu, t-Bu, cyclohexyl, perfluorobutyl,
phenyl, methoxyphenyl, bromophenyl, 4-methoxynaphthalene,
naphthalene, and adamantyl. Examples of P2 are commercially
available from Wako Chemical.
The polymer component of the photosensitive compositions comprises
an alkali soluble resin component whose alkali solubility is
suppressed by the presence of acid sensitive moieties and whose
alkali solubility is returned by treatment with an acid and,
optionally, heat; wherein said polymer comprises one or more
polymers comprising the monomer unit (C). ##STR20##
wherein R.sup.13 is selected from H, C.sub.1 -C.sub.4 lower alkyl,
CN, or CH.sub.2 CO.sub.2 R.sup.20 ; R.sup.14 and R.sup.15 are each
independently selected from H, linear or branched C.sub.1 -C.sub.4
alkyl, or halogen; R.sup.16 is H, or branched or linear C.sub.1
-C.sub.4 alkyl; R.sup.17 is selected from substituted or
unsubstituted phenyl, a substituted or unsubstituted linear,
branched or cyclic C.sub.1 -C.sub.20 alkyl, optionally containing
an ether or ester group, a substituted or unsubstituted
phenylalkylene or a substituted or unsubstituted C.sub.6 -C.sub.20
cyclic alkylene; R.sup.18 and R.sup.19 are each independently
selected from H, linear or branched or cyclic C.sub.1 -C.sub.14
alkyl, or C.sub.7 -C.sub.14 alicyclic; R.sup.20 is a C.sub.1
-C.sub.14 branched linear or cyclic alkyl, substituted or
unsubstituted phenyl, or C.sub.7 -C.sub.14 alicyclic. Each polymer
comprising the monomer C in the photosensitive composition
comprises from about 10% to about 90% of the total polymer.
Preferred polymers comprising the monomer unit (C) are those in
which R.sup.13, R.sup.14, R.sup.15, R.sup.16, R.sup.18, and
R.sup.19 =H. More preferred polymers comprising the monomer unit C
are those in which R.sup.13, R.sup.14, R.sup.15, R.sup.16,
R.sup.18, and R.sup.19,=H and R.sup.17 is selected from C.sub.1
-C.sub.4 linear or branched alkyl, or a substituted or
unsubstituted C.sub.6 -C.sub.20 cyclic alkylene or a substituted or
unsubstituted linear, branched or cyclic C.sub.1 -C.sub.20 alkyl,
optionally containing an ether or ester group. Most preferred
polymers comprising the monomer unit C are those in which R.sup.13,
R.sup.14, R.sup.15, R.sup.16, R.sup.18, and R.sup.19,=H and
R.sup.17 is selected from C.sub.1 -C.sub.4 linear or branched
alkyl, or a substituted or unsubstituted C.sub.6 -C.sub.20 cyclic
alkylene.
Polymers and copolymers comprising the monomer unit (C) can be
synthesized by polymerization of the corresponding styrenic
precursor to monomer unit (C) using any suitable means of
polymerization known to those in the art. If this method is
employed, then the styrenic precursor is typically synthesized from
the reaction of hydroxystyrene with the corresponding alpha halo
ether under basic conditions.
A preferred method of synthesis of polymers and copolymers
comprising the monomer unit (C) is to prepare hydroxystyrene
polymers and copolymers via standard polymerization methods (e.g.
free radical) and then react the polymer with a vinyl ether (D)
under acidic conditions. Examples of suitable syntheses may be
found in U.S. Pat. Nos. 5,670,299 and 6,033,826 herein incorporated
by reference. ##STR21##
An alternatively preferred method is to react the hydroxystyrene
polymer or copolymer with a vinyl ether (e.g. t-butyl vinyl ether)
in the presence of an alcohol (R.sup.17 --OH) and an acid catalyst.
Examples of this synthetic process can be found in U.S. Pat. Nos.
6,159,653, 6,133,412 and 6,309,793, herein incorporated by
reference.
Each polymer employed in this invention may contain more than one
different monomer unit (C).
The polymer employed in this invention may further comprise
additional monomers. Suitable monomers include radical
polymerizable vinyl monomers such as acrylates, methacrylates,
vinyl ethers, vinyl esters, substituted and unsubstituted styrenes
and the like. In an additional preferred embodiment, the preferred
polymers further comprise monomer units of hydroxystyrene.
In an additional embodiment, base additives may be added to the
photoresist composition. The purpose of the base additive is to
scavenge protons present in the photoresist prior to being
irradiated by the actinic radiation. The base prevents attack and
cleavage of the acid labile groups by the undesirable acids,
thereby increasing the performance and stability of the resist. The
percentage of base in the composition should be significantly lower
than the photoacid generator because it would not be desirable for
the base to interfere with the cleavage of the acid labile groups
after the photoresist composition is irradiated. The preferred
range of the base compounds, when present, is about 3% to 50% by
weight of the photoacid generator compound. Nitrogenous bases are
preferred. Suitable examples of base additives are
2-methylimidazole, tetramethyl ammonium hydroxide,
tetrabutylammonium hydroxide, triisopropylamine,
4-dimethylaminopryidine, 4,4'-diaminodiphenyl ether,
2,4,5-triphenylimidazole, and 1,5-diazabicyclo[4.3.0]non-5-ene, and
1,8-diazabicyclo[5.4.0]undec-7-ene.
Dyes may be added to the photoresist to increase the absorption of
the composition to the actinic radiation wavelength. The dye must
not poison the composition and must be capable of withstanding the
process conditions including any thermal treatments. Examples of
suitable dyes are fluorenone derivatives, anthracene derivatives or
pyrene derivatives. Other specific dyes that are suitable for
photoresist compositions are described in U.S. Pat. No. 5,593,812,
which is incorporated herein by reference.
The photoresist composition may further comprise conventional
additives, such as adhesion promoters, dissolution inhibitors, and
surfactants. A person skilled in the art will be able to choose the
appropriate desired additive and its concentration.
The photoresist composition is applied uniformly to a substrate by
known coating methods. For example, the coatings may be applied by
spin-coating, dipping, knife coating, lamination, brushing,
spraying, and reverse-roll coating. The coating thickness range
generally covers values of about 0.1 to more than 10 .mu.m. After
the coating operation, the solvent is generally removed by drying.
The drying step is typically a heating step called `soft bake`
where the resist and substrate are heated to a temperature of about
50.degree. C. to 150.degree. C. for about a few seconds to a few
minutes; preferably for about 5 seconds to 30 minutes depending on
the thickness, the heating element and end use of the resist.
The photoresist compositions are suitable for a number of different
uses in the electronics industry. For example, it can be used as
electroplating resist, plasma etch resist, solder resist, resist
for the production of printing plates, resist for chemical milling
or resist in the production of integrated circuits. The possible
coatings and processing conditions of the coated substrates differ
accordingly.
For the production of relief structures, the substrate coated with
the photoresist composition is exposed imagewise. The term
`imagewise` exposure includes both exposure through a photomask
containing a predetermined pattern, exposure by means of a computer
controlled laser beam which is moved over the surface of the coated
substrate, exposure by means of computer-controlled electron beams,
and exposure by means of X-rays or UV rays through a corresponding
mask.
Radiation sources, which can be used, are all sources that emit
radiation to which the photoacid generator is sensitive. Examples
include high pressure mercury lamp, KrF excimer lasers, ArF excimer
lasers, electron beams and x-rays sources.
The process described above for the production of relief structures
preferably includes, as a further process measure, heating of the
coating between exposure and treatment with the developer. With the
aid of this heat treatment, known as "post-exposure bake",
virtually complete reaction of the acid labile groups in the
polymer resin with the acid generated by the exposure is achieved.
The duration and temperature of this post-exposure bake can vary
within broad limits and depend essentially on the functionalities
of the polymer resin, the type of acid generator and on the
concentration of these two components. The exposed resist is
typically subjected to temperatures of about 50.degree. C. to
150.degree. C. for a few seconds to a few minutes. The preferred
post exposure bake is from about 80.degree. C. to 130.degree. C.
for about 5 seconds to 300 seconds.
After imagewise exposure and any heat treatment of the material,
the exposed areas of the photoresist are removed by dissolution in
a developer. The choice of the particular developer depends on the
type of photoresist; in particular on the nature of the polymer
resin or the photolysis products generated. The developer can
include aqueous solutions of bases to which organic solvents or
mixtures thereof may have been added. Particularly preferred
developers are aqueous alkaline solutions. These include, for
example, aqueous solutions of alkali metal silicates, phosphates,
hydroxides and carbonates, but in particular of tetra alkylammonium
hydroxides, and more preferably tetramethylammonium hydroxide
(TMAH). If desired, relatively small amounts of wetting agents
and/or organic solvents can also be added to these solutions.
Synthetic Procedures
PAG Synthesis Example 1
Synthesis of 4-(1-butoxyphenyl)diphenylsulfonium Mesylate
In a 500 ml, round bottom flask equipped with a reflux condenser
was combined n-butyl phenyl ether (40.4 g, 0.269 mol),
diphenylsulfoxide (48 g, 0.237 mol) and Eaton's Reagent (154 g). An
exothermic reaction occurred. The reaction mixture was maintained
at 50-55.degree. C. with stirring for 5 hours. The reaction mixture
was then added to deionized water (1200 ml). This mixture was
stirred for 30 minutes. The mixture was extracted two times with
toluene (2.times.300 ml). The pH of the lower aqueous layer was
adjusted to 8-8.5 by addition of a 25% aqueous solution of
tetramethylammonium hydroxide (573.0 g).
PAG Synthesis Example 2
Synthesis of 2,4,6-trimethylphenyidiphenylsulfonium Mesylate
In a 1 L, round bottom flask equipped with a reflux condenser was
combined 1,3,5-trimethylbenzene (40 g, 0.333 mol),
diphenylsulfoxide (67.3 g, 0.333 mol) and Eaton's Reagent (160 g).
An exothermic reaction occurred. The reaction mixture was
maintained at 50-55.degree. C. with stirring for 5 hours. The
reaction mixture was then added to deionized water (800 ml). This
mixture was stirred for 30 minutes. The mixture was extracted two
times with toluene (2.times.250 ml). The pH of the lower aqueous
layer was adjusted to 8-8.5 by addition of a 25% aqueous solution
of tetramethylammonium hydroxide (889.6 g).
PAG Synthesis Example 3
Synthesis of sodium bis-(perfluorobutanesulfonyl)imide
In a 250 ml beaker equipped with a stirbar and a pH meter was
combined bis-(perfluorobutanesulfonyl) amide (15 g, 60% acid w/w in
water, 0.0155 mol) and deionized water (105 g). To the solution,
sodium hydroxide (approximately 1.9 g, 33% w/w in water) was slowly
added until the pH was above 7.0. The solution became viscous. The
solution was maintained at room temperature with stirring for 15
minutes. The salt solution was used immediately and without further
work-up in subsequent PAG synthesis.
PAG Synthesis Example 4
Synthesis of sodium bis-(perfluoroethanesulfonyl)imide
In a 250 ml beaker equipped with a stirbar and a pH meter was
combined bis-(perfluoroethanesulfonyl) amide (2.0 g, 0.00525 mol)
and deionized water (30 g). To the solution, sodium hydroxide
(approximately 0.7 g, 33% w/w in water) was slowly added until the
pH was above 7.0. The solution was maintained at room temperature
with stirring for 15 minutes. The salt solution was used
immediately and without further work-up in subsequent PAG
synthesis.
PAG Synthesis Example 5
Synthesis of 4-(1-butoxyphenyl)diphenylsulfonium
bis-(perfluorobutanesulfonyl)imide (PAG 1)
To a previously prepared solution containing 0.00517 mol sodium
bis-(perfluorobutanesulfonyl)imide in 35 grams water was added 2.23
grams (0.00517 mol) of 4-(1-butoxyphenyl)diphenylsulfonium
mesylate. A white suspension immediately formed. 50 ml of ethyl
acetate was then added to the suspension. The resulting mixture was
stirred for 24 hours. The bottom water layer was removed. The ethyl
acetate layer was washed four times with 40 ml portions of
deionized water. The ethyl acetate layer was then dried over
magnesium sulfate. The magnesium sulfate was removed by filtration.
Ethyl acetate was removed from the filtrate on a rotary evaporator
affording 3.87 grams of a viscous oil. The .sup.19 F NMR spectrum
contained the following resonance bands: .delta. -80.8(t, 3F),
-112.7(t, 2F), -120.6(t, 2F), -125.6(q, 2F). The .sup.1 H NMR
contained: .delta. 1.0(t, 3H), 1.5(sextet, 2H), 1.8(pentet, 2H),
4.2(t, 2H), 7.4(d, 2H), 7.9(multiplet, 12H).
PAG Synthesis Example 6
Synthesis of 4-(1-butoxyphenyl)diphenylsulfonium
bis-(perfluoroethanesulfonyl)imide (PAG 2)
To a previously prepared solution containing 0.00694 mol sodium
salt prepared in Example 4 in 38 grams water was added 2.99 grams
(0.00694 mol) of 4-(1-butoxyphenyl)diphenylsulfonium mesylate. A
white suspension immediately formed. 50 ml of ethyl acetate was
then added to the suspension. The resulting mixture was stirred for
24 hours. The bottom water layer was removed. The ethyl acetate
layer was washed four times with 40 ml portions of deionized water.
The ethyl acetate layer was then dried over magnesium sulfate. The
magnesium sulfate was removed by filtration. Ethyl acetate was
removed from the filtrate on a rotary evaporator affording 4.3
grams of a viscous oil. The .sup.19 F NMR spectrum contained the
following resonance bands: .delta. -80.1(s, 3F), -118.3(s, 2F). The
.sup.1 H NMR contained: .delta. 1.0(t, 3H), 1.5(sextet, 2H),
1.8(pentet, 2H), 4.2(t, 2H), 7.4(d, 2H), 7.9(multiplet, 12H).
PAG Synthesis Example 7
Synthesis of 2,4,6-trimethylphenyldiphenylsulfonium
bis-(perfluorobutanesulfonyl)imide (PAG 3)
To a previously prepared solution containing 0.00523 mol sodium
salt prepared in Example 3 in 40 grams water was added 2.10 grams
(0.00523 mol) of 2,4,6-trimethylphenyldiphenyl sulfonium mesylate.
A white suspension immediately formed. 60 ml of ethyl acetate was
then added to the suspension. The resulting mixture was stirred for
24 hours. The bottom water layer was removed. The ethyl acetate
layer was washed four times with 40 ml portions of deionized water.
The ethyl acetate layer was then dried over magnesium sulfate. The
magnesium sulfate was removed by filtration. Ethyl acetate was
removed from the filtrate on a rotary evaporator affording 3.71
grams of a viscous oil. The .sup.19 F NMR spectrum contained the
following resonance bands: .delta. -82.2(t, 3F), -114.2(t, 2F),
-121.9(t, 2F), -127.1(q, 2F). The .sup.1 H NMR contained: .delta.
2.2(s, 6H), 2.3(s, 3H), 7.3(s, 2H), 7.8(multiplet, 10H).
PAG Synthesis Example 8
Synthesis of 2,4,6-trimethylphenyidiphenylsulfonium
bis-(perfluoroethanesulfonyl)imide (PAG 4)
To a previously prepared solution containing 0.00689 mol sodium
salt prepared in Example 2 in 40 grams water was added 2.76 grams
(0.00689 mol) of 2,4,6-trimethylphenyidiphenylsulfonium mesylate. A
white suspension immediately formed. 60 ml of ethyl acetate was
then added to the suspension. The resulting mixture was stirred for
24 hours. The bottom water layer was removed. The ethyl acetate
layer was washed four times with 40 ml portions of de-ionized
water. The ethyl acetate layer was then dried over magnesium
sulfate. The magnesium sulfate was removed by filtration. Ethyl
acetate was removed from the filtrate on a rotary evaporator
affording 3.4 grams of a solid. The .sup.19 F NMR spectrum
contained the following resonance bands: .delta. -80.0(s, 3F),
-118.3(s, 2F). The .sup.1 H NMR contained: .delta. 2.2(s, 6H),
2.3(s, 3H), 7.3(s, 2H), 7.8(multiplet, 10H).
PAG Synthesis Example 9
Synthesis of toluenediphenylsulfonium
bis-(perfluorobutanesulfonyl)imide (PAG 5)
To a previously prepared solution containing 0.00344 mol sodium
salt prepared in Example 3 in 51 grams water was added 1.39 grams
(0.00344 mol) of toluenediphenylsulfonium iodide. 70 grams of ethyl
acetate was then added to the suspension. The resulting mixture was
stirred for 48 hours. The bottom water layer was removed. The ethyl
acetate layer was washed three times with 40 ml portions of
deionized water. The ethyl acetate layer was then dried over
magnesium sulfate. The magnesium sulfate was removed by filtration.
Ethyl acetate was removed from the filtrate on a rotary evaporator
affording 2.78 grams of a semi-viscous oil. The .sup.19 F NMR
spectrum contained the following resonance bands: .delta. -82.2(t,
3F), -114.2(t, 2F), -121.9(t, 2F), -127.1(q, 2F). The .sup.1 H NMR
contained: .delta. 2.5(s, 3H), 7.7(d, 2H), 7.9(multiplet, 12H).
PAG Synthesis Example 10
Synthesis of toluenediphenylsulfonium
bis-(perfluoroethanesulfonyl)imide (PAG 6)
To a previously prepared solution containing 0.00525 mol sodium
salt prepared in Example 4 in 60 grams water was added 2.12 grams
(0.00525 mol) of toluenediphenylsulfonium iodide. 51 grams of ethyl
acetate was then added to the suspension. The resulting mixture was
stirred for 48 hours. The bottom water layer was removed. The ethyl
acetate layer was washed three times with 40 ml portions of
deionized water. The ethyl acetate layer was then dried over
magnesium sulfate. The magnesium sulfate was removed by filtration.
Ethyl acetate was removed from the filtrate on a rotary evaporator
affording 2.56 grams of an oil. The .sup.19 F NMR spectrum
contained the following resonance bands: .delta. -80.1(s, 3F),
-118.4(s, 2F). The .sup.1 H NMR contained: .delta. 2.5(s, 3H),
7.7(d, 2H), 7.9(multiplet, 12H).
PAG Synthesis Example 11
Synthesis of toluenediphenylsulfonium-(trifluoromethyl
perfluorobutylsulfonyl)imide (PAG 7)
To a previously prepared solution containing 0.0034 mol lithium
salt of trifluoromethyl perfluorobutylsulfonyl)imide (obtained from
3M Corporation) in 50 grams water was added 1.39 grams (0.0034 mol)
of toluenediphenylsulfonium iodide. 70 ml of ethyl acetate was then
added to the suspension. The resulting mixture was stirred for 24
hours. The bottom water layer was removed. The ethyl acetate layer
was washed four times with 40 ml portions of deionized water. The
ethyl acetate layer was then dried over magnesium sulfate. The
magnesium sulfate was removed by filtration. Ethyl acetate was
removed from the filtrate on a rotary evaporator affording 2.8
grams of a white solid. The .sup.19 F NMR spectrum contained the
following resonance bands .delta. -80.3(s, 3F), -82.1(tt, 3F),
-114.3(s, 2F), -122.02(m, 2F), -127.01(q, 2F). The .sup.1 H NMR
contained: .delta. 2.5(s, 3H), 7.7(d, 2H0), 7.9(multiplet,
12H).
PAG Synthesis Example 12
Synthesis of tris-(tert-butylphenyl)sulfonium-(trifluoromethyl
perfluorobutylsulfonyl)imide (PAG 8)
To a previously prepared solution containing 0.0034 mol lithium
salt of trifluoromethyl perfluorobutylsulfonyl)imide (obtained from
3M Corporation) in 50 grams water was added 1.78 grams (0.0034 mol)
of tris-(tert-butylphenyl)sulfonium tetrafluoroborate. 70 ml of
ethyl acetate was then added to the suspension. The resulting
mixture was stirred for 24 hours. The bottom water layer was
removed. The ethyl acetate layer was washed four times with 40 ml
portions of deionized water. The ethyl acetate layer was then dried
over magnesium sulfate. The magnesium sulfate was removed by
filtration. Ethyl acetate was removed from the filtrate on a rotary
evaporator affording 2.52 grams of a white solid. The .sup.19 F NMR
spectrum contained the following resonance bands .delta. -80.1(s,
3F), -82.3(tt, 3F), -114.3(s, 2F), -122.02(m, 2F), -127.01(q, 2F).
The .sup.1 H NMR contained: .delta. 1.4(s, 27H), 7.8(AB quartet,
12H).
Polymer P1
Preparation of
4-[1-(2-cyclohexylethoxy)-ethoxy]styrene-co-4-[1-(t-butoxy)-ethoxy]styrene
-co-4-hydroxy styrene-co-4-t-butylstyrene Copolymer
A 250 mL round-bottom, three-necked flask was equipped with a
temperature probe, a magnetic stir bar and closed vacuum adapter.
134.9 g of propylene glycol monomethyl ether acetate (PGMEA) was
charged into the flask. 30.0 g of powdered
poly(hydroxystyrene-co-t-butylstyrene) (93:7)(MW 12780; PD 1.9) was
added to the stirring solvent. The mixture was stirred for 30
minutes to form a homogeneous solution. The mixture was heated to
60.degree. C. and vacuum was applied to the solution to distill
48.92 g of the solvent. The solution was allowed to cool to room
temperature under nitrogen atmosphere. 4.15 g of tertiary-butyl
vinyl ether and 4.69 g 2-cyclohexylethanol were added to the
homogeneous solution. 0.30 g of 1% para-toluene sulfonic acid
(prepared by dissolving 1 g of acid in 99 g of PGMEA) was added.
After a brief, mild exotherm, the solution was allowed to stir at
23.degree. C. for 4 hours. 3.77 g of 1% triethylamine solution in
PGMEA was added to the reaction mixture to quench the acid. The
reaction mixture was stirred for an additional 30 minutes. The
polymer solution was transferred to a 500 mL separatory funnel and
treated with 115 g of acetone, 46 g of hexanes and 46 g of
de-ionized water. The mixture was shaken for about 30 seconds to a
minute and allowed to separate into two layers. The lower, aqueous
layer was discarded. The top organic layer was subjected to two
more washings. In the second washing, 23 g of acetone, 7 g of PGMEA
and 23 g of deionized water were used and in the third washing, 17
g of acetone, 7 g of PGMEA and 23 g of deionized water were
used.
The top organic layer was transferred to a 500 mL round-bottom,
three-necked flask equipped with a temperature probe, magnetic stir
bar and a vacuum distillation assembly. The flask was placed on a
heating mantle. Acetone and hexane were removed by atmospheric
distillation. Water and some PGMEA were removed by azeotropic
vacuum distillation at 66.degree. C. until the solids content of
the distillation flask was about 30.17%. Analytical data is found
in the table. The structure of the polymer is given below (a=0.76;
b=0.07; c=0.04; d=0.13). ##STR22##
Polymer P2
Polymer P2 is [4-(1-ethoxyethoxy)styrene-co-4-hydroxystyrene 37:63]
(MWP-240, a product of Wako Chemical].
Polymer P3
Polymer P3 is poly[(4-hydroxystyrene)-co-(tertiary-butyl
acrylate)-co-(isobornyl acrylate)] (61:25:14) MW: which was custom
synthesized by TriQuest, LP. The molecular weight was 16,600
daltons.
General Formulation Procedure
Photoresist components as described in the examples were mixed in
an amber-bottle and stirred until a homogeneous solution was
obtained. The solution was filtered through a 0.2 .mu.m filter into
a clean amber-bottle.
General Lithographic Procedure 1
Silicon wafers were first spun coated with DUV42P BARC (a product
of Brewer Science, Inc., Rolla, Mo.) and proximity baked for 70
seconds at 205.degree. C. to yield a BARC thickness of 62 nm. The
resist samples were then applied over the BARC layer and prebaked
on a hotplate for 90 seconds (temperature setting depended on the
particular example) resulting in a resist film thickness of 325 nm.
The resist samples were then exposed pattern-wise with a KrF
excimer laser beam (248 nm) in a Canon FPA-3000 EX6 stepper through
a photo mask containing a line/space pattern. A numerical aperture
of 0.65NA was utilized, with a 2/3 annular setting. The exposed
resist coated wafers were then subjected to PEB treatment on a
110.degree. C. hot plate for 90 seconds. A 60 second puddle
development treatment in a 0.262 N solution of tetramethylammonium
hydroxide followed. The data was collected using a Hitachi Scanning
Electron Microscope. The resist images were sheared
cross-sectionally, and the images were magnified 80 k times.
General Lithographic Procedure 2
General Lithographic Procedure 2 is identical to General
Lithographic Procedure 1 except that the BARC thickness was 80 nm
and the photoresist thickness was 360 nm.
EXAMPLES 1-6
Formulations for Examples 1-6 were prepared as described in the
General Formulation Procedure using various
bis(perfluoroalkylsulfonyl)imide type PAGs,
bis(t-butylsulfonyl)diazomethane (Wako Chemical), Polymer P1,
Polymer P2, 1,8-diazobicyclo[5.4.0]undec-7-ene (DBU),
tris[2-(2-methoxyethoxy)ethyl]amine (TMEA), antipyrene, and PGMEA
according to the amounts listed in Table 1. Amounts listed in Table
1 are in units of grams. Formulations for Examples 1-6 were
lithographically evaluated using General Lithographic Procedure 1.
The wafers were examined in a scanning electron microscope for
photospeed, resolution, DOF, and profile. The results are given in
Table 2 with the corresponding softbake temperatures employed.
Energy to size in Table 2 refers to the energy to resolve 130 nm
line-space patterns with equal line and space widths.
TABLE 1 bis(per- bis(perfluoro Poly- Poly- Bis(tert- fluoro-
alkylsulfonyl) mer mer butylsulfonyl) alkylsulfonyl) imide PAG
Anti- Ex. P1 P2 diazomethane imide PAG Amount DBU TMEA pyrene PGMEA
1 5.899 4.826 0.660 PAG 1 0.552 0.033 0.006 0.017 88.00 2 5.899
4.826 0.660 PAG 2 0.552 0.033 0.006 0.017 88.00 3 5.806 4.750 0.660
PAG 3 0.720 0.033 0.006 0.017 88.00 4 5.806 4.750 0.660 PAG 4 0.720
0.033 0.006 0.017 88.00 5** 6.181 5.057 -- PAG 3 0.720 0.032 -- --
88.00 6** 5.806 4.750 -- PAG 1 0.720 0.033 0.006 0.017 88.00
**Comparative Examples
TABLE 2 Softbake Energy to DOF Profile Temperature PEB Size
Resolution @ 130 nm Surface Ex. (.degree. C.) (.degree. C.)
(mJ/cm2) (.mu.m) (.mu.m) Slope Quality Comments 1 130 110 60 0.13
0.1 Vertical very Slight sw's cuspy 2 130 110 63 0.13 0.3 Vertical
Flat, Slight sw's Cusp 3 130 110 60 0.13 0.2 Vertical Flat, Slight
sw's Cusp 4 130 110 55 0.13 0.4 Vertical Flat, Slight sw's Cusp 5**
130 110 44 0.13 0.9 Vertical round top Slight sw's 6** 130 110 46
0.13 0.6 Vertical Round Slight sw's Top **Comparative Examples
The data in Table 2 indicates that rounded profile tops obtained
using bis(perfluoroalkylsulfonyl)imide type PAGs can be improved in
unoptimized formulations by the use of a bissulfonyldiazomethane
type PAG.
EXAMPLES 7-24
Formulations for Examples 7-24 were prepared as described in the
General Formulation Procedure using PAG 8 (the PAG from PAG
Synthesis Example 12), bis(t-butylsulfonyl)diazomethane (Wako
Chemical), Polymer P1, Polymer P2,
1,8-diazobicyclo[5.4.0]undec-7-ene (DBU),
tris[2-(2-methoxyethoxy)ethyl]amine (TMEA), antipyrene, and PGMEA
according to the amounts listed in Table 3. Amounts listed in Table
3 are in units of grams. Formulations for Examples 7-24 were
lithographically evaluated using the General Lithographic Procedure
2. Several formulations were evaluated using different softbake
conditions. In those cases, the results are additionally marked
with the letters a, b or c in Table 4. The wafers were examined in
a scanning electron microscope for photospeed, resolution, DOF, and
profile. The results are given in Table 4 with the corresponding
softbake temperatures employed. Energy to size in Table 4 refers to
the energy to resolve 130 nm line-space patterns with equal line
and space widths.
TABLE 3 Bis(tert- Polymer Polymer butylsulfonyl) Ex. P1 P2
diazomethane PAG 8 DBU TMEA Antipyrene PGMEA 7 5.796 4.742 0.176
0.264 0.015 -- 0.007 89.00 8 5.796 4.742 0.176 0.264 0.019 -- 0.003
89.00 9 5.796 4.742 0.176 0.264 0.022 -- -- 89.00 10 5.637 4.612
0.286 0.429 0.025 -- 0.011 89.00 11 5.637 4.612 0.286 0.429 0.030
-- 0.005 89.00 12 5.637 4.612 0.286 0.429 0.036 -- -- 89.00 13
5.478 4.482 0.396 0.594 0.035 -- 0.015 89.00 14 5.478 4.482 0.396
0.594 0.042 -- 0.007 89.00 15 5.478 4.482 0.396 0.594 0.050 -- --
89.00 16 5.743 4.699 0.209 0.314 0.024 -- 0.010 89.00 17 5.695
4.660 0.242 0.363 0.028 -- 0.012 89.00 18 5.792 4.739 0.176 0.264
0.021 -- 0.009 89.00 19** 5.669 4.638 -- 0.660 0.020 0.03 0.010
89.00 20 5.605 4.586 0.077 0.693 0.023 0.004 0.012 89.00 21 5.605
4.586 0.308 0.462 0.039 -- -- 89.00 22 5.605 4.586 0.154 0.616
0.039 -- -- 89.00 23 5.764 4.716 0.099 0.396 0.025 -- -- 89.00 24
5.605 4.586 0.308 0.462 0.023 0.004 0.012 89.00 **Comparative
Example
TABLE 4 Soft- bake Energy Tem- to Size DOF @ 130 nm Profile
Comments perature (mJ/ Surface Standing Ex. (.degree. C.) cm2)
(.mu.m) Slope Quality Wave 7a 100 31 0.6 Vertical Flat Low sw's 7b
130 32 NA Retrograde Flat, Cusp Moderate sw's 8 115 37 0.9 Vertical
Flat, Rough Slight sw's 9a 100 41.5 0.75 Slight Slope Round Top Low
sw's 9b 130 39 NA Retrograde Flat, Cusp Slight sw's 10 100 37 0.8
Slight Slope Round Top Low sw's 11a 115 43 0.9 Slight Slope Flat,
Rough Slight sw's 11b 130 44.5 0.7 Vertical Flat, Cusp Moderate
sw's 12 115 44.5 0.85 Slight Slope Flat Top Slight sw's 13a 100
41.5 0.5 Moderate Round Top Low sw's Slope 13b 115 39 0.9 Slight
Slope Round Top Slight sw's 13c 130 41.5 0.7 Moderate Round Top
Slight Slope sw's 14 100 53.5 0.6 Moderate Round Top Low sw's Slope
15a 100 55 0.7 Very Sloped Round Top Low sw's 15b 130 52 0.8 Slight
Slope Flat, Cusp Moderate sw's 16 100 42 0.8 Vertical Flat Slight
sw's 17 100 43 0.8 Vertical Flat Low sw's 18 100 41 0.8 Vertical
Flat, Rough Low sw's 19** 130 37 0.4 Very Sloped Film Loss, Slight
Round sw's 20 130 36 0.4 Very Sloped Film Loss, Slight Round sw's
21 130 47 0.75 Very Sloped Film Loss, Moderate Round sw's 22 130 43
0.75 Vertical Flat Moderate sw's 23 130 38 0.7 Slight Slope Flat
Heavy sw's 24 130 38 0.5 Vertical Flat, Rough Moderate sw's
**Comparative Example
Data in Table 4 shows that when bis(perfluoroalkylsulfonyl)imide
type PAGs were used as the sole PAG in the acetal protected PHS
based formulations, (Example 19) sloped profiles with rounded tops,
unexposed film thickness loss and poor DOF were obtained. However,
use of the bissulfonyldiazomethane type PAG as a co-PAG resulted in
obtaining a vertical profile with flat tops, no unexposed film
loss, and excellent DOF (e.g. Example 11).
EXAMPLES 25-26
Formulation examples 25 and 26 were prepared as described in the
General Formulation Procedure using PAG 8 (the PAG from PAG
Synthesis Example 12), tris-(tert-butylphenyl)sulfonium
bis-(perfluorobutanesulfonyl)imide (PAG 9 obtained from the 3M
Corporation), Polymer P1, Polymer P2,
bis(t-butylsulfonyl)diazomethane,
1,8-diazobicyclo[5.4.0]undec-7-ene (DBU), antipyrene and propylene
glycol monomethyl ether acetate (PGMEA) according to the amounts
listed in Table 5. Amounts listed in Table 5 are in units of grams.
Formulation Examples 25 and 26 were lithographically evaluated
using the General Lithographic Procedure 2. The wafers were
examined in a scanning electron microscope for photospeed,
resolution, DOF, and profile. The results are given in Table 6 with
the corresponding softbake temperatures employed. Energy to size in
Table 6 refers to the energy to resolve 130 nm line-space patterns
with equal line and space widths.
TABLE 5 bis(per- bis(perfluoro- Bis(tert- fluoro- alklysulfonyl)
Polymer Polymer butylsulfonyl) alkylsulfonyl) imide Anti- Ex. P1 P2
diazomethane imide PAG PAG amount DBU pyrene PGMEA 25 5.796 4.742
0.242 PAG 9 0.363 0.028 0.012 89.00 26 5.796 4.742 0.242 PAG 8
0.363 0.028 0.012 89.00
TABLE 6 Energy to Size Softbake Resolu- (130 Tem- tion nm) DOF
Profile Comments perature Dense (mJ/ @ 130 nm Surface Standing Ex.
(.degree. C.) Ln cm2) (.mu.m) Slope Quality Wave 25 130 130 40 0.5
Slight Round Low sw's nm Slope 26 130 130 40 0.8 Slight Flat Low
sw's nm Slope
Results in Table 6 suggest that unsymmetric
bis-(perfluorobutanesulfonyl)imides have slightly improved
performance over symmetrical
bis-(perfluorobutanesulfonyl)imides.
EXAMPLES 27-30
Formulations for Examples 27-30 were prepared as described in the
General Formulation Procedure using PAG 8 (the PAG from PAG
Synthesis Example 12), tris-(tert-butylphenyl)sulfonium
bis-(perfluorobutanesulfonyl)imide (PAG 9 obtained from the 3M
Corporation), Polymer P3, bis(t-butylsulfonyl)diazomethane,
1,8-diazobicyclo[5.4.0]undec-7-ene (DBU),
tris[2-(2-methoxyethoxy)ethyl]amine (TMEA), antipyrene and
propylene glycol monomethyl ether acetate (PGMEA) according to the
amounts listed in Table 7. Amounts listed in Table 7 are in units
of grams. Formulations for Examples 27-30 were lithographically
evaluated using the General Lithographic Procedure 2. The wafers
were examined in a scanning electron microscope for photospeed,
resolution, DOF, and profile. The results are given in Table 8 with
the corresponding softbake temperatures employed. Energy to size in
Table 8 refers to the energy to resolve 130 nm line-space patterns
with equal line and space widths.
TABLE 7 Bis(tert- butyl- sulfonyl) Polymer PAG diazo- PAG Anti- Ex.
P3 8 methane 9 DBU pyrene PGMEA 27 10.355 0.363 0.242 -- 0.028
0.012 89.00 28 10.355 -- 0.242 0.363 0.028 0.012 89.00 29 10.307
0.66 -- -- 0.02 0.01 89.00 30** 10.307 -- -- 0.66 0.02 0.01 89.00
**Comparative Example
TABLE 8 Softbake Energy Tem- to Size Profile Comments perature (mJ/
DOF @ 130 nm Surface Standing Ex. (.degree. C.) cm2) (.mu.m) Slope
Quality Wave 27 140 75* DNR Retrograde Flat, Low Cusp*** sw's*** 28
140 84* DNR Retrograde Round, Low Cusp*** sw's*** 29 140 44 0.8
Sloped Round Heavy sw's 30** 140 48 0.4 Slight Slope Round Heavy
sw's *did not resolve **Comparative Example ***on 140 nm
features
The lithographic results in Table 8 show that in an ESCAP type
polymer matrix, the use of a bissulfonyidiazomethane type co-PAG
blend with bis(perfluoroalkylsulfonyl)imide type PAGs had an
adverse effect on the lithographic performance.
EXAMPLES 31 AND 32
Formulations for Examples 31 and 32 were prepared as described in
the General Formulation Procedure using PAG 8 (the PAG from PAG
Synthesis Example 12), tris-(tert-butylphenyl)sulfonium
perfluorobutanesulfonate (TTBPS-nonaflate), Polymer P1, Polymer P2,
bis(t-butylsulfonyl)diazomethane,
1,8-diazobicyclo[5.4.0]undec-7-ene (DBU),
tris[2-(2-methoxyethoxy)ethyl]amine (TMEA), antipyrene and
propylene glycol monomethyl ether acetate (PGMEA) according to the
amounts listed in Table 9. Amounts listed in Table 9 are in units
of grams. Formulations for Examples 31 and 32 were lithographically
evaluated using the General Lithographic Procedure 2 and under an
alternate film thickness condition of 340 nm as noted in Table 10.
The wafers were examined in a scanning electron microscope for
photospeed, resolution, DOF, and profile. The results are given in
Table 10 with the corresponding softbake temperatures employed.
Energy to size in Table 10 refers to the energy to resolve 130 nm
line-space patterns with equal line and space widths.
TABLE 9 Bis(tert- Polymer Polymer butylsulfonyl) co-PAG Anti- Ex.
P1 P2 diazomethane co-PAG amount DBU TMEA pyrene PGMEA 31** 5.467
4.473 0.605 TTBPS- 0.403 0.03 0.005 0.015 89.00 Nonaflate 32 5.61
4.586 0.308 PAG 9 0.462 0.039 -- 0 89.00 **Comparative Example
TABLE 10 Energy Softbake to Size DOF Resist Profile Comments
Temperature Resolution (130 nm) @ 130 nm Film Thickness Surface
Standing Ex. (.degree. C.) Dense Ln (mJ/cm2) (.mu.m) (nm) Slope
Quality Wave 31a** 130 130 nm 48 0.6 340 Slight Round Slight sw's
Slope 31b** 130 130 nm 46 0.3 360 Vertical Flat, Moderate Cusp sw's
32a 130 130 nm 48 0.7 340 Vertical Round Moderate sw's 32b 130 130
nm 47 0.7 360 Vertical Flat Moderate sw's **Comparative Example
The results in Table 10 illustrate the problem in prior art resists
of photoresist performance change with changes in photoresist film
thickness. Such film thickness differences occur when photoresist
is coated over substrates with existing topography. The prior art
formulation in Example 31 has significantly different and lower DOF
at photoresist film thicknesses differing only by 20 nm. At one
film thickness, the DOF is limited by bridging of the images. At
the other photoresist film thickness, DOF is limited by line
collapse. The formulation of this invention (Example 32) is not as
limited by these problems and thus has higher and less variable DOF
with changes in photoresist film thickness.
EXAMPLES 33-38
Formulations for Examples 33-38 were prepared as described in the
General Formulation Procedure using combinations of various
bis(perfluoroalkylsulfonyl)-imide type PAGs, one of two
bis(sulfonyl)diazomethane co-PAGs, Polymer P1, Polymer P2,
1,8-diazobicyclo[5.4.0]undec-7-ene (DBU), antipyrene, and 89 parts
PGMEA according to the amounts listed in Table 11. Amounts listed
in Table 11 are in parts. The formulations were lithographically
tested employing General Lithographic Procedure 2 using a
110.degree. C. softbake for all formulations. Results are tabulated
in Table 12.
TABLE 11 Second First bis(per- bis(per- Bis(sulfonyl) fluoro-
fluoro- Second Polymer Polymer diazomethane/ alkylsulfonyl) First
PAG alkylsulfonyl) PAG Anti- Ex. P1 P2 amount imide PAG amount
imide PAG Amount DBU pyrene 33** 5.706 4.669 t-butyl/0.605 0.014
0.006 34 5.701 4.146 t-butyl/0.121 PAG 8 0.182 PAG 3 0.182 0.021
0.009 35 10.365 0 t-butyl/0.242 PAG 8 0.362 0.021 0.009 36 5.696
4.142 t-butyl/0.242 PAG 6 0.363 0.027 0.012 37 5.701 4.664
Cyclohexyl/0.242 PAG 8 0.363 0.021 0.009 38 5.696 4.142
t-butyl/0.242 PAG 9 0.182 PAG 10* 0.182 0.027 0.012 **Comparative
Example *PAG 10 =
tris-(tert-butylphenyl)sulfonium-bis-(trifluoromethanesulfonyl)imide
obtained from the 3M Corporation.
TABLE 12 Energy to Softbake Size (130 Profile Temperature PEB nm)
Resolution DOF @ 130 nm Surface Standing Ex. (.degree. C.)
(.degree. C.) (mJ/cm2) (.mu.m) (.mu.m) Slope Quality Waves 33** 110
110 32 0.13 0.2 Retrograde Round Low 34 110 110 48 0.13 0.6 Slight
Slope Flat Slight 35 110 110 38 0.13 0.4 Vertical Flat Low 36 110
110 35 0.13 0.6 Slight Slope Round Slight 37 110 110 45 0.13 0.8
Vertical Round Moderate 38 110 110 48 0.13 0.6 Slight Slope Round
Slight **Comparative Example
Results from these experiments show that addition of symmetrical or
unsymmetrical perfluorosulfonyl imide type PAG or mixtures thereof
to bis(sulfonyl) diazomethane type PAGs improves lithographic
performance.
While the invention has been described herein with reference to the
specific embodiments thereof, it will be appreciated that changes,
modification and variations can be made without departing from the
spirit and scope of the inventive concept disclosed herein.
Accordingly, it is intended to embrace all such changes,
modification and variations that fall with the spirit and scope of
the appended claims.
* * * * *